There is a lot of folklore about left-brain, right-brain differences—the right side of the brain is supposed to be the creative side, while the left is the logical half. But it’s much more complicated than that. Marnie Halpern studies how left-right differences arise in the developing brain and discovers the genes that control this asymmetry.

Using the tiny zebrafish, Danio rerio, Halpern explores how regional specializations occur within the neural tube, the embryonic tissue that develops into the brain and spinal cord. The zebrafish is ideal for these studies because its basic body plan is set within 24 hours of fertilization. By day five, young larvae are able to feed and swim, and within three months they are ready to reproduce. They are also prolific breeders. Most importantly the embryos are transparent, allowing scientists to watch the nervous system develop and to identify mutants easily.

In the course of studying a mutation that produced fused eyes analogous to those of the mythological Cyclops, Halpern and a team from Vanderbilt University discovered that the affected gene codes for a protein signal that acts in the early embryo, then later reappears on the left side of the neural tube. This unexpected finding led her to explore where in the larval brain the molecular asymmetry resided and to determine its purpose.

Notable structural specializations are found within a precise region of the fish forebrain, and Halpern found that the signal influences whether they end up on the left or the right side. Remarkably, a member of the very same protein family had previously been shown to control the left and right differences in our internal organs, such as the characteristic rightward looping and left positioning of the heart, the counterclockwise coiling of the intestines, and the placement of the pancreas on the left and the gall bladder and liver on the right side of the body.

The Halpern laboratory has studied diverse problems using this versatile fish and its powerful genetics, initiating new projects to understand the basis of neural tube defects, to study patterning of the skeleton, and to visualize digestive physiology, projects that have enabled former trainees to establish unique research directions in their own laboratories. Other current interests of the Halpern group include the genetic regulation of myelination—the process of myelin synthesis. Myelin is the insulating material that forms around the axons of neurons to expedite their electrical activity and that is compromised in multiple sclerosis.

Halpern is also very involved in outreach. Among her activities she runs a speakers program with the Baltimore public schools, Women Serious About Science, which encourages girls from diverse backgrounds to pursue careers in science. She received her B.Sc. in biology from McMaster University and her master’s at the McMaster University Medical Centre. She then went on to Yale for her Ph.D. and did postdoctoral work at the Institute of Neuroscience, University of Oregon. She joined the Carnegie staff in 1994. For more see the Halpern lab

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May 7, 2018

Baltimore, MD—Allan C. Spradling, Director Emeritus of Carnegie’s Department of Embryology, has been awarded the 23rd March of Dimes and Richard B. Johnson, Jr., MD Prize in Developmental Biology as “an outstanding scientist who has profoundly advanced the science that underlies our understanding of prenatal development and pregnancy.”

Department director and Carnegie co-interim president Yixian Zheng remarked, “Allan is a legend in developmental biology. We are all delighted by this well- deserved recognition of Allan’s groundbreaking research.”

Spradling’s decades of scientific accomplishments cover a broad spectrum of advancements. Since the early 20th century, the fruit

Carnegie Science, Carnegie Institution, Carnegie Institution for Science, Neta Schwartz
November 27, 2017

Washington, DC—Not too long ago, biologists would induce mutations in an entire genome, isolate an organism that displayed a resulting disease or abnormality that they wanted to study, and then work backward to determine which gene was responsible for the defect.  This process often took years to yield definitive results.

Now, thanks to the CRISPR/Cas9 genome-editing tool, biologists can target specific genes for mutation and then see how this induced mutation manifests in an organism—tackling the problem from the other direction. But they are finding that the expected physical changes don’t always occur.

Why?

New work from Carnegie’s Steven Farber and Jennifer

Carnegie Science, Carnegie Institution, Carnegie Institution for Science,
July 13, 2017

Baltimore, MD— The brain is the body’s mission control center, sending messages to the other organs about how to respond to various external and internal stimuli. Located in the forebrain, the habenular region is one such message-conducting system. Two new papers from Carnegie scientists explain how the habenulae develop and their unsuspected role in recovering from fear.

Found in all vertebrates, the bilaterally paired habenulae regulate the transmission of dopamine and serotonin, two important chemicals related to motor control, mood, and learning.

Previous research has shown that the habenular system is involved in modulating sleep cycles, anxiety, and pain and reward

Carnegie Science, Carnegie Institution, Carnegie Institution for Science,
July 6, 2017

Washington, D.C.--Yixian Zheng has been selected to direct Carnegie’s Department of Embryology in Baltimore, Maryland. She has been Acting Director since February 1st of 2016.

Carnegie president Matthew Scott remarked, “Yixian has been an exceptional leader of the department as Acting Director. We are extremely pleased that she took on this job permanently.  Her fascinating science, independent thinking, vision, extraordinary management skills, and perfect temperament are a tremendous asset to Carnegie Science.”

The Zheng lab has a long-standing interest in cell division and the cytoskeleton—the lattice arrangement of rods and fibers and motors that gives shape to cells and

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The Zheng lab studies cell division including the study of stem cells, genome organization, and lineage specification. They study the mechanism of genome organization in development, homeostasis—metabolic balance-- and aging; and the influence of cell morphogenesis, or cell shape and steructure,  on cell fate decisions. They use a wide range of tools and systems, including genetics in model organisms, cell culture, biochemistry, proteomics, and genomics.

 

The Spradling laboratory studies the biology of reproduction. By unknown means eggs reset the normally irreversible processes of differentiation and aging. The fruit fly Drosophila provides a favorable multicellular system for molecular genetic studies. The lab focuses on several aspects of egg development, called oogenesis, which promises to provide insight into the rejuvenation of the nucleus and surrounding cytoplasm. By studying ovarian stem cells, they are learning how cells maintain an undifferentiated state and how cell production is regulated by microenvironments known as niches. They are  also re-investigating the role of steroid and prostaglandin hormones in controlling the

Stem cells make headline news as potential treatments for a variety of diseases. But undertstanding the nuts and bolts of how they develop from an undifferentiated cell  that gives rise to cells that are specialized such as organs, or bones, and the nervous system, is not well understood. 

The Lepper lab studies the mechanics of these processes. overturned previous research that identified critical genes for making muscle stem cells. It turns out that the genes that make muscle stem cells in the embryo are surprisingly not needed in adult muscle stem cells to regenerate muscles after injury. The finding challenges the current course of research into muscular dystrophy, muscle

The Marnie Halpern laboratory studies how left-right differences arise in the developing brain and discovers the genes that control this asymmetry. Using the tiny zebrafish, Danio rerio, they explores how regional specializations occur within the neural tube, the embryonic tissue that develops into the brain and spinal cord.

The zebrafish is ideal for these studies because its basic body plan is set within 24 hours of fertilization. By day five, young larvae are able to feed and swim, and within three months they are ready to reproduce. They are also prolific breeders. Most importantly the embryos are transparent, allowing scientists to watch the nervous system develop and to

Staff member Nick Konidaris joined Carnegie in October 2017. He works on a variety of new optical instrumentation projects in astronomy. He  recently began working on a new development platform for the 40-inch Swope telescope at Carnegie's Las Campanas Observatory. It is called the Rapid Response Swope Spectrograph and Imager (R2S2I). When operational, it will be a workhorse instrument and development platform.

Prior to Carnegie, he was director of product management at Kairos Aerospace in Mountain View, CA. Konidaris received a B.S. in physics from Carnegie Mellon University, and conducted coursework in electrical engineering before obtaining a Ph.D. in astrophysics from the

Experimental petrologist Michael Walter became director of the Geophysical Laboratory beginning April 1, 2018. His recent research has focused on the period early in Earth’s history, shortly after the planet accreted from the cloud of gas and dust surrounding our young Sun, when the mantle and the core first separated into distinct layers. Current topics of investigation also include the structure and properties of various compounds under the extreme pressures and temperatures found deep inside the planet, and information about the pressure, temperature, and chemical conditions of the mantle that can be gleaned from mineral impurities preserved inside diamonds.

Walter had been at

Guoyin Shen's research interests lie in the quest to establish and to examine models for explaining and controlling the behavior of materials under extreme conditions. His research activities include investigation of phase transformations and melting lines in molecular solids, oxides and metals; polyamorphism in liquids and amorphous materials; new states of matter and their emergent properties under extreme conditions; and the development of enabling high-pressure synchrotron techniques for advancing compression science. 

He obtained a Ph.D. in mineral physics from Uppsala University, Sweden in 1994 and a B.S. in geochemistry from Zhejiang University, China in 1982. For more

Leopoldo Infante became the director of the Las Campanas Observatory on July 31, 2017.

Since 2009, Infante has been the founder and director of the Centre for Astro-Engineering at the Chilean university. He joined PUC as an assistant professor in 1990 and has been a full professor since 2006. He was one of the creators of PUC’s Department of Astronomy and Astrophysics, and served as its director from 2000 to 2006. He also established the Chilean Astronomical Society (SOCHIAS) and served as its president from 2009 to 2010.

Infante received his B.Sc. in physics at PUC. He then acquired a MSc. and Ph.D. in physics and astronomy from the University of Victoria in Canada.